1. Field of the Invention
Embodiments of the present invention generally relate to networking and, more particularly, to hub and spoke network models.
2. Description of the Related Art
A hub and spoke network model is one where a hub (having one or more routers) acts as the intermediary for all traffic sent to the spokes (other nodes in the network). Assuming a network with two spokes, spoke 1 and Spoke 2, for Spoke 1 to communicate with Spoke 2, traffic from spoke 1 is sent to the hub, which then sends the traffic to Spoke 2. Routing all traffic through the hub may allow centralized application of policies, providing a level of security on the network. Such a model is useful, particularly, when there are no links between the spokes, or when there are only low-speed links between the spokes, and the links between the hub and the spokes are high-speed.
The term multicast generally refers to the delivery of messages from a single source to a group of destinations simultaneously over a network. Ideally, the messages are delivered only once to each destination, and messages are duplicated only when communication links to the destinations split into separate links to separate destinations. To efficiently send multicast messages, it is common to form multicast groups and establish neighbor relationships between adjacent nodes. However, this technique is not readily available in hub and spoke networks, because the spokes do not communicate with each other directly.
Accordingly, what is needed is a technique for efficiently sending multicast messages in a hub and spoke network.